ENGLISH

6卷/4期

6卷/4期

華藝線上圖書館

Pages:

1-26

論文名稱

利用衛星資料求取大氣氣溶膠光學厚度之研究及其在大氣環境檢測之應用

Title

Applying Satellite Data for Aerosol Optical Depth and Atmospheric Environment Monitoring

作者

林唐煌 , 劉振榮 , 陳哲俊

Author

Tang-Huang Lin , Gin-Rong Liu , A. J. Chen

中文摘要

大氣的氣溶膠不僅模糊了地表的資訊,亦嚴重地影響大氣的環境及氣候的變遷,在地球資源的遙測與大氣環境的變遷是相當重要的參數之一,也因此有許多利用衛星資料求取氣溶膠參數的方法陸續的提出,密暗像元法和對比法則為較常被應用的兩種方法。而本文之研究重點則在於結構函數法之測試及改進,研究結果經地面實測的氣溶膠光學厚度之驗證,獲得極佳之準確度,顯示改進後的結構函數法在台灣地區具有極高之實用性及適用性。此外,在空氣品質監測的應用亦為本研究重點之一,其最重要的兩個步驟包括高精度大氣氣溶膠光學厚度之取得,以及具代表性的氣溶膠粒徑參數之建立,均可由本研究中獲得。應用結果證實利用衛星觀測資料檢測空氣品質具極高之可行性,將可進一步建立台灣地區之即時空氣品質檢(監)測系統。此外,研究結果亦可應用於衛星影像之大氣校正。

Abstract

Since aerosol are one of the most important factors in the atmospheric correction of remotely sensed data, many methods have been developed in retrieving the aerosol optical depth (AOD). The dark dense vegetation (DDV) and contrast reduction method are two concepts which are mostly used for the estimation of AOD. The main aim of this study is to improve the structure function method, which lies within the contrast reduction approach, in retrieving the AOD over Taiwan. The results compared with in-site observations show significant improvements in the accuracy of the retrieved AOD. On the other hand, the optical depth and size distribution of aerosol are key parameters in the monitoring of the air quality. The two can be constructed in this study as the results indicate a high practicality in applying satellite data for the monitoring of the atmospheric environment.

關鍵字

密暗植被、氣溶膠光學厚度、結構函數、氣溶膠粒徑參數

Keywords

Dense Dark Vegetation (DDV), Aerosol Optical Depth (AOD), Structure Function, Aerosol Size Distribution

附件檔名

華芸線上圖書館

N / A

備註說明

200112-6-4-1-26

Pages:

27-54

論文名稱

從都市區立體航照影像中萃取屋頂面的實用策略

Title

A Practical Strategy for Roof Patch Extraction from Urban Stereo Aerial Images

作者

邱式鴻 , 王蜀嘉

Author

Shih-Hong Chio , Shue-Chia Wang

中文摘要

都市區建物的三維幾何模型(簡稱建物模型)對許多應用是非常基本且重要的資訊。然而都市區航照影像的複雜程度,往往使得建物模型的萃取工作非常困難。經過多年的研究,體驗到要從複雜的航照影像中萃取建物模型,全自動化的方式在目前仍不可行,適時的人工干預仍是必要的。所以,本文的重點就是要提出一個較實用的策略來萃取建物的模型,研究在利用航照立體影像對萃取建物模型的過程中,如何更有效地將人的判釋能力整合至萃取策略中。而由論述和試驗中,說明本文所提由全自動化的方式萃取航照影像中相關的幾何特徵物,接著導出有意義的 3-D 線段並自動偵測可能的屋頂面邊界線,然後再用交談式方式重建建物模型的萃取策略,將能克服萃取都市區屋頂模型的複雜問題。

Abstract

Building geometric models are elementary but indispensable information in many applications. After years of researches, it is generally recognized that human intervention in the extraction procedure for build­ing geometric models from aerial images is necessary. Therefore, this paper will present a practical strategy that effectively integrates the capability of human interpretation with the computed powers of computers to extract the building models from urban stereo image pairs. In this proposed strategy, we suggest the rel­evant geometric features are extracted and the possible roof boundaries are detected by automatic approaches. Subsequently, the geometrical models of roof patches are reconstructed by interactive operations. The operator only plays the assistant role but very important intelligent interpretation task in this proposed strategy. Experiments show our proposed practical strategy is feasible and applicable. The accuracy of reconstructed roof patches is good enough for some practical applications.

關鍵字

交談式、建物重建、語意資訊、多法則

Keywords

interactive, building reconstruction, semantic information, multiple algorithms

附件檔名

華芸線上圖書館

N / A

備註說明

200112-6-4-27-54

Pages:

55-74

論文名稱

COSMIC 計畫 GPS 掩星技術反演大氣溫度與壓力之模擬誤差分析

Title

A Simulated Error Analysis of Temperature and Pressure Retrieval Using the GPS Occultation Technique for the COSMIC Project

作者

高士杰 , 楊名

Author

Shih-Chieh Kao , Ming Yang

中文摘要

本文提出利用 GPS (Global Positioning System) 掩星技術探測地球大氣溫度與壓力之模擬誤差分析。 GPS掩星技術是利用低軌衛星觀測來自高軌GPS衛星的訊號,進一步反演地球大氣溫度與壓力垂直剖面,以提供氣象預報及全球變遷等研究之應用。本文首先回顧反演大氣溫度與壓力之演算法則,並探討積分截尾誤差、GPS 衛星軌道誤差、COSMIC (Constellation Observing System for Meteorology Iono-sphere and Climate ) 衛星軌道誤差、以及 GPS 相位觀測量隨機誤差對 GPS 掩星技術反演大氣溫度與壓力之影響。實驗顯示當使用COSMIC精密軌道時,上述各項誤差來源在對流層及平流層部分對反演壓力之影響均不顯著(小於 O.2mb) ;在溫度反演方面,不同來源之誤差在對流層部分之影響量較小(小於 lK),而在較高的平流層部分之影響量則有明顯提升的趨勢,可達到約 10K 之量級。目前國際上GPS 掩星觀測成果仍存有一個尚未確切理解的問題,即在地表 45 公里以上反演所得的溫度經常出現波狀的擺動;而根據實驗成果顯示,此類波狀的擺動亦可能由GPS觀測量之偶然誤差所造成,並不必然為真實大氣溫度之變化。

Abstract

This paper presents a simulated error analysis of the GPS (Global Positioning System) occultation technique, which is used by the joint Taiwan-U.S. COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) project to study the Earth's atmosphere and monitor temperature and pressure profiles. A qualitative description of the GPS occultation technique of atmosphere limb sounding is reviewed, and retrieval algorithms for temperature and pressure profiles determination in the absence of water vapor are summarized in this paper. A simulation study was conducted to investigate the impact of various error sources, including integral truncation error, GPS and COSMIC orbit errors, and measurement noises, on the retrieved temperature and pressure profiles. Simulation results show that the induced effects of the above error sources on atmospheric pressure retrieval were less than O.2mb when precise COSMIC orbit ephemeris was used. The corresponding impacts on the retrieved temperature profiles were small (less than 1K) in the troposphere; however, they were substantially greater in the stratosphere (~ 10K). To date, there still remains an outstanding problem in GPS occultation data analysis - the retrieved temperature often displays wave-like fluctuations in the upper atmosphere (> 45km). According to the simulation results contained in this paper, these wave-like motions do not necessarily represent the actual atmospheric temperature behavior; they could also reflect the induced error pattern of the GPS measurement noises.

關鍵字

COSMIC 衛星、GPS 掩星技術、誤差分析、大氣溫度與壓力

Keywords

COSMIC satellites, GPS occultation technique, error analysis, atmospheric temperature and pressure

附件檔名

華芸線上圖書館

N / A

備註說明

200112-6-4-55-74

Pages:

75-86

論文名稱

「技術短文」近景數化影像半自動式混凝土裂縫量測

Title

Mensuration of Concrete Cracks Using Digitized Close-Range Photographs

作者

陳良健 , 田永銘 , 詹皇祥

Author

Liang-Chien Chen , Yong-Ming Tien , Huang-Hsiang Jan

中文摘要

混凝土結構物中之成分受到化學反應將會產生膨脹現象,致而誘發裂縫生成,裂縫將會造成混凝土劣化,影響結構物之耐久性及強度。 在傳統實務上乃採用接觸性方式量測。然而單一裂縫之寬度並非為一定值,且有人工量測之偏差存在。因此採用接觸性方式量測有相當多之不便與困擾存在。遂乃提出一套使用非接觸性量測方式來分析膨脹量與裂縫寬度間之關係以彌補現行實務上之不足處,並滿足對量測結果之一致性與重複性。 裂縫搜尋中為了提高其成果之可靠性因此採用半自動之方式來搜尋裂縫,除利用灰階資訊外尚再加上附加條件之輔助以得較佳之成果。為使求解更具穩定性,先使用高斯函數對資料作平滑化處理以減少雜訊干擾,並利用差分近似微分,算出像點的灰度梯度大小,俟透過取閥值等操作便可將邊緣檢出。 將所搜尋出之裂縫邊界處與人工所數化之結果作一比較,以瞭解所提出之搜尋方式與人工所數化結果間之差異。

Abstract

The elements of concrete structures suffering from chemical reactions trend to be an expansion phenomenon, which lead to cracks. The concrete structures of inferior quality caused by cracks have much influence on the structures durability and strength. The non-contact measurement is employed because of the physical limitations in manual measurements. This paper deals with semi-automatic crack feature extraction from digital close-range images to infer the relationship between concrete expansion and crack width. Only few manual seed points are required on crotches of crack features. Then, the shape and position may be illustrated with automatic feature extraction in two- dimensional image space. In the process of crack searching, a Gaussian filter is applied in advance to smooth the noise along crack profiles to improve the reliability and precision. Subsequently, the edges of cracks are determined by computing the gradient of the crack profiles. The edges of cracks detected by the proposed algorithm will be compared with the one digitized by manual operations.

關鍵字

近景、半自動、裂縫

Keywords

close-range, Semi-automatic, crack

附件檔名

華芸線上圖書館

N / A

備註說明

200112-6-4-75-86

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